The Portuguese Atlas of Valladolid (Sixteenth Century): A Geometric Reassessment

Abstract

A study of two Portuguese nautical charts of the sixteenth century, here designated as the ‘Atlas of Valladolid’, has been carried out with the aim of determining their origin and date of compilation. These charts are little known among the international community and have never been subjected to a cartometric analysis. Based on stylistic considerations, on the comparison of the toponyms with other contemporary charts and on the analysis of the latitude errors, it is concluded that the two charts were likely to have been drawn by the Portuguese cartographer Gaspar Viegas before 1534.

L’Atlas portugais de Valladolid (XVI^e siècle): une réévaluation géométrique

Une étude de deux cartes nautiques portugaises du XVI^e siècle, ici désignées sous le nom d’‘Atlas de Valladolid’, a été conduite pour déterminer leur origine et leur date de compilation. Ces cartes sont peu connues de la communauté internationale et n’ont jamais fait l’objet d’une analyse cartométrique. Sur la base de considérations stylistiques, de comparaisons de toponymes avec d’autres cartes marines contemporaines et de l’analyse des erreurs de latitudes, on conclut que les deux cartes ont probablement été dressées par le cartographe portugais Gaspar Viegas avant 1534.

Der portugiesische Atlas von Valladolid (16. Jahrhundert): eine geometrische Neubewertung

Zwei portugiesische Seekarten des 16. Jahrhunderts—hier als ‘Atlas von Valladolid’ bezeichnet—wurden mit dem Ziel untersucht, ihre Herkunft und das Datum ihrer Zusammenstellung zu bestimmen. Diese Seekarten sind in der internationalen Forschung wenig bekannt und wurden noch nie kartometrisch untersucht. Aufgrund von stilistischen Zuschreibungen, dem Vergleich ihrer Toponyme mit denen gleichzeitig angefertigter Karten und der Analyse der Fehler in Bezug auf die geographische Breite kommt der Autor zu dem Schluss, dass die beiden Karten von dem portugiesischen Kartographen Gaspar Viegas in der Zeit vor 1534 gezeichnet wurden.

El atlas portugués de Valladolid (siglo XVI): una revaluación geométrica

Un estudio de dos cartas naúticas portuguesas del siglo XVI, aquí designadas como el Atlas de Valladolid, fue llevado a cabo con el objetivo de determinar su origen y fecha de compilación. Estas cartas son poco conocidas entre la comunidad internacional y nunca han sido sometidas a análisis cartométricos. A partir de consideraciones estilísticas, de la comparación de los topónimos con otras cartas contemporáneas y del análisis de los errores de latitud, se concluye que las dos cartas fueron probablemente dibujadas por el cartógrafo portugués Gaspar Viegas antes de 1534.

Keywords:

• Atlas of Valladolid
• portolan charts
• Africa
• cartometric analysis
• toponyms
• Gaspar Viegas

Notes

^1. Mariano Cuesta Domingo and Jesús Varela Marcos, ‘El portulano de Valladolid’, in Juan Vernet, El tratado de Tordesillas en la cartografia historica (Valladolid, Junta de Castilla y León, 1994), 151–65.

^2. Cuesta Domingo and Varela Marcos justified 1500 as a terminus post quem by the presence of toponyms in the vicinity of the Cape of Good Hope that only started to appeared on charts after Bartolomeu Dias’s voyage (1488). They suggested 1525 as the latest possible date by the depiction of the mythic island of Santa Cruz, which, they said, had practically disappeared from charts by 1519. They were apparently unaware that Santa Cruz is also portrayed on Gaspar Viegas’s Atlantic chart (1534). See Cuesta Domingo and Varela Marcos, ‘El Portulano de Valladolid’ (note 1), 163.

^3. Ibid., 163–64.

^4. Cuesta Domingo and Varela Marcos, Atlas Portulano de Valladolid 1500 (Valladolid, Ayuntamiento de Valladolid, 1996), 70–72. In this book, the authors withdrew all the conclusions reported in their earlier article, ‘El Portulano de Valladolid’ (see note 1), relating to the purpose, origin and dating of the atlas. The reasons for such a volte-face were not given, but a nationalistic factor may be suspected. Yet in a paper, delivered in 1998 during the IX lnternational Reunion for the History of Nautical Science and Hydrography, Varela Marcos suggested that the charts might have been made by Cristopher Columbus after 1498, during his stay in Portugal. Once again, the author appears to have withdrawn all the conclusions reported in the earlier works, but no material evidence or convincing arguments were produced for this conjecture. See Jesús Varela Marcos, ‘El Portulano de Valladolid, ejemplo de cartografia colombina’, in Proceedings of the IX International Reunion for the History of Nautical Science and Hydrography, ed. Inácio Guerreiro and Francisco Contente Domingues (Cascais, 1999), 365‒75 (https://www.academia.edu/6701208/_IX_VARELA_MARCOS_Jesus_-_El_Portulano_de_Valladolid_ejemplo_de_cartografia_colombina).

^5. ‘También se aprecia una malla de base con cuadrados perfectos, recordando las cartas de Marino de Tiro … ’ This is a clear reference to the old (erroneous) thesis that the latitude charts of the 16th century were constructed according to the principles of the cylindrical equidistant projection (the so-called ‘square chart’). In the present case, it is possible that the authors were misled by the transparency of the vellum and the visibility of lines drawn for the chart on the other side, although a careful examination of the charts clearly denies such possibility (see Fig. 1 and Plate 1). See Cuesta Domingo and Varela Marcos, ‘El Portulano de Valladolid’ (note 1), 159; and idem, Atlas Portulano de Valladolid 1500 (note 4), 48–49. See also Joaquim Alves Gaspar, ‘The myth of the square chart’, e-Perimetron 2:2 (2007): 66–79 (http://www.e-perimetron.org/Vol_2_2/Gaspar.pdf).

^6. Only three extant works have been attributed so far to Gaspar Viegas; a chart of the Atlantic (1534; Bibliothèque nationale de France, Cartes et plans, CPL GE B-1132 (RES)), and two anonymous atlases of c.1537 (Florence, Biblioteca Riccardiana, Cod. Ricc. 1813; Florence, Archivio di Stato di Firenze, Carta naut. 11, Invent. Som. 17, ex Med. Pal. 2135). See Armando Cortesão and Avelino Teixeira da Mota, Portugaliae Monumenta Cartographica, 6 vols. (Lisboa, Comissão para a Comemoração do V Centenário da Morte do Infante D. Henrique, 1960; Lisboa, Imprensa Nacional-Cada da Moeda, 1987 [facsimile edition]), 1: 115‒21.

^7. The two earliest charts with this type of scale are the anonymous chart of the Mediterranean and western Europe of c.1510 (Munich, Bayerische Staatsbibliothek, Cod. icon. 138/40) attributed to Pedro Reinel, and an anonymous chart of the southern Atlantic and Indian Oceans of c.1510 (Bayerische Staatsbibliothek, Guelf Aug. Fol. 98-K) attributed to his son Jorge Reinel. In the two oldest extant charts with a scale of latitudes, Pedro Reinel’s chart of the northern Atlantic and western Mediterranean (c.1504, Bayerische Staatsbibliothek, Cod. icon. 132) and the now lost anonymous chart of the Atlantic Ocean, c.1506 (known as Kunstmann III; facsimile by Otto Progel, 1843; Bibliothèque national de France, CPL GE B-1120 (RES)), the scales are of a different type. I have not been able to discover a single example of a Portuguese chart using a scale of this type after 1537, the date attributed to the two anonymous atlases by Gaspar Viegas.

^8. The length L of the degree of latitude on a chart, expressed in leagues, is determined by the expression L = R×N/S, where R is the length of a degree of latitude in millimeters, N is the number of leagues contained in each section (12½ leagues, in the present case), and S is the length of one section.

^9. The only known charts using this standard are those comprising the Miller Atlas (1519, Paris, Bibliothèque nationale de France), which are attributed to Lopo Homem, Pedro Reinel and Jorge Reinel.

^10. It has to be stressed that estimating the value of a module is not an exact process. Tiny differences when taking measurements on all charts, but especially those on a small scale, are unavoidable.

^11. For a more detailed explanation of the process as applied to the Cantino planisphere, see Joaquim Alves Gaspar, ‘Blunders, errors and entanglements: scrutinizing the Cantino planisphere with a cartometric eye’, Imago Mundi 64:2 (2012): 191–94; idem, ‘From the Portolan Chart of the Mediterranean to the Latitude Chart of the Atlantic: Cartometric Analysis and Modeling’ (doctoral thesis, Lisboa, Instituto Superior de Estatística e Gestão da Informação, Universidade Nova de Lisboa, 2010), 58–61.

^12. The Cantino planisphere (1502, Modena, Biblioteca Estense Universitaria); the lost anonymous chart of c.1506 known as Kunstmann III; an anonymous chart of c.1510 attributed to Jorge Reinel; the lost anomymous chart of c.1517 attributed to Pedro Reinel; Diogo Ribeiro’s planisphere (1529, Biblioteca Vaticana); and Gaspar Viegas’s chart of 1534 (Paris, Bibliothèque nationale de France).

^13. For a particular chart, S = [1/N ∑(φ_i − φ_v)²]^½, where φ_i is the latitude of place i, φ_V is the latitude of the same place in the atlas and N is the number of places.

^14. See Cuesta Domingo and Varela Marcos, ‘El Portulano de Valladolid’ (note 1), 163.